This invention relates to the preparation of 1-carvone from 1-.alpha.- or 1-.beta.-pinene by microbiological means.
1-Carvone, a ketonic terpene, is a major constituent of spearmint oil and is an important flavoring substance that is widely used for example, in chewing gum, toothpaste, toiletries and in food and drinks.
In the past 1-carvone has either been isolated from natural spearmint oil or manufactured by complex synthetic chemical reactions, for example as described in U.S. Pat. No. 2,796,428. A number of attempts have also been described to obtain 1-carvone by microbiological means. Thus in Japanese published patent application No. 47-38998 a process is described for the preparation of carvone from limonene using an organism belonging to the genus Corynebacteria. The degradation of .alpha.-pinene by bacteria has been described in Fermentation Technology Today (1972) 609; however, although a number of terpenoid degradation products were identified, including in particular cis-thujone and trans-carveol, there is no suggestion that 1-carvone may be produced by this process.